The present invention relates to methods and apparatus for interfacing transmission lines to electrical and optical equipment. In particular, the present invention relates to methods and apparatus for interfacing a high-density of transmission lines, such as electrical cables and optical fibers, with equipment.
Interface plates are used in networking equipment to provide an interface between connections external to a certain piece of equipment or circuit card and connections on a circuit card or opto-electrical circuit pack housed within a chassis. Some interface plates are used to house connectors, such as connector barrels, mating sleeves, connectors, feedthroughs or adapters. These connector interface plates transmit signals between transmission lines terminated by a connector, such as electrical cables or optical fibers and electrical and optical equipment. In many known optical communication systems, fiber optical ribbon connectors or discrete optical fiber connectors are used to connect a plurality of optical fibers to the optical communication equipment.
Interfacing optical fibers to equipment is particularly difficult. Care must be taken when handling and connecting optical fiber cables to connectors because optical fibers cannot be wound or bent to a radius less than a predetermined minimum radius without the occurrence of microcracks, which may cause loss of data. Thus, practical high-density optical connectors must allow a technician to easily connect optical fibers to the optical connector. Practical high-density optical connectors must also allow a technician to easily disconnect optical fibers from connectors for cleaning or reconfiguring the system. For example, technicians may need to connect and disconnect and clean optical fibers connected to the equipment as part of installation, maintenance and repair.
Many state-of-the-art optical fiber communications system use wavelength division multiplexing (WDM), which is an optical transport technology that propagates many wavelengths in the same optical fiber. WDM systems effectively increase the aggregate bandwidth per fiber to the sum of the bit rates of each wavelength. Bandwidths greater than 1 terabit/sec have been demonstrated in WDM based communication systems.
Dense Wavelength Division Multiplexing (DWDM) is a technology that implements WDM technology in a communication system with a large number of wavelengths. DWDM is typically used to describe WDM technology that propagates more than 40 wavelengths in a single optical fiber. As the number of wavelengths in a DWDM communication system increases, the number of electrical cables and optical fibers required to interface with the DWDM system increases. Thus, the number of electrical cables and optical fibers that require connection to the interface plates increases. However, the surface area available to interface electrical cables and optical fibers in an equipment installation may be limited.
The present invention relates to high-density electrical and optical connectors. These connectors or mating sleeves reside on interface plates as described herein. In one embodiment, an interface plate according to the present invention includes a curved outer surface that extends over useful connector surface area in order to increase the number of electrical and optical connectors compared with a flat interface plate. The curved outer surface includes a plurality of interface connectors. In one embodiment, the interface plate includes connectors oriented at an angle relative to a normal line extending from a normal angle to the curved outer surface.
Accordingly, the present invention features a high-connector density interface plate comprising a curved outer surface having a plurality of interface connectors. Each of the plurality of interface connectors is adapted to receive a cable at an angle relative to a normal line extending from a normal angle to the curved outer surface. The curved outer surface increases the interface plate surface area available for interface connections relative to an interface plate having a flat outer surface.
In one embodiment, the interface connectors may be optical fiber connectors, such as optical fiber interface sleeves, adaptors, or barrels. For example, the interface connections may be for OC 768, OC192, OC48, or 10 Gigabit Ethernet (GE) optical fiber signals. The connectors or sleeves may be for a variety of optical connectors such as SC, FC, APC, ST, LC or Mu connectors. In another embodiment, the interface connectors may be electrical interface connectors, such as RF signal interface connectors, microwave signal interface connectors, and millimeter wave signal interface connectors.
In one embodiment, the angle of at least one of the plurality of interface connectors relative to the normal line extending from the normal angle to the curved outer surface is substantially zero. In another embodiment, the angle of at least one of the plurality of interface connectors relative to the normal line extending from the normal angle to the curved outer surface is non-zero. In yet another embodiment, the angle relative to the normal line extending from the normal angle to the curved outer surface for at least one of the plurality of interface connectors is different from another angle relative to another normal line extending from another normal angle to the curved outer surface for a different one of the plurality of interface connectors.
The present invention also features a signal interface for an optical fiber communication system that includes an interface plate having curved outer surface that is adapted to receive a plurality of interface connectors. The curved outer surface increases the surface area available for interface connectors relative to an interface plate having a flat outer surface. A plurality of interface connectors is positioned through the curved outer surface. Each of the plurality of interface connectors is adapted to receive an external transmission line at an angle relative to a normal line extending from a normal angle to the curved outer surface.
In one embodiment, the angle of at least one of the plurality of interface connectors relative to a normal line extending from a normal angle to the curved outer surface is substantially zero. In another embodiment, the angle of at least one of the plurality of interface connectors relative to a normal line extending from a normal angle to the curved outer surface is substantially non-zero. In yet another embodiment, the angle relative to the normal line extending from the normal angle to the curved outer surface for at least one of the plurality of interface connectors is different from another angle relative to another normal line extending from another normal angle to the curved outer surface for a different one of the plurality of interface connectors.
The present invention also features a method of connecting an optical fiber to an optical fiber communication system. The method includes positioning an interface connector having an internal port and an external port on an interface plate having a curved outer surface. The curved outer surface increases the surface area available for interface connectors relative to an interface plate having a flat outer surface.
An internal fiber optic cable is coupled to the internal port of the interface connector. An external fiber optic cable is coupled to the external port of the interface connector at an angle relative to a normal line extending from a normal angle to the curved outer surface. In one embodiment, the angle relative to the normal line extending from the normal angle is zero. In another embodiment, the angle relative to the normal line extending from the normal angle is non-zero.